The primary differentiating factors among different Roulette games include the wheel layout, the number of pockets, and the rules governing bets and payouts. For instance, European Roulette features a single zero (0), while American Roulette has both a single zero (0) and a double zero (00), which increases the house edge in the latter. The type of bets allowed can also vary; some versions may offer unique betting options or different payout structures.